1. Field of the Invention
This invention relates to bulk paper and waste shredding systems. In particular the invention addresses problems associated with handling of the material during shredding operations.
2. Description of the Prior Art
Shredding systems for confidential waste material are now commonly utilized in mobile shredding facilities. The art has evolved to now require unique solutions to problems encountered in practical settings of these shredding systems while taking into account the required efficiency of the overall shredding process.
Because of the nature of the material being shredded, i.e. of confidential nature and not to be lost from the shredding bin before it is shredded, the shredding system is made mobile so the shredding operator can travel to the site of a client or similar who has confidential waste for shredding. Alternatively, the confidential waste would have to be transported to a central shredding facility, with the added risk that confidential material might accidentally be lost from the transport.
Even when a mobile shredding system is used, the confidential material inside a bin has to be lifted up and dumped into a hopper leading to a shredder. During the lifting, there is a risk that confidential material will spill from the bin, for example blown away by the wind. To safeguard against this, an enclosure has been provided, which can be pulled out from a storage position to an operating position in which the enclosure generally covers the bin on its way up to be emptied.
In general, a shredding operator bills his or her clients by weight of shredded material. Traditionally, each bin is weighed using a transportable scale before it is attached to the bin lifting mechanism and emptied into the hopper. This has the apparent drawbacks of necessitating the manipulation of the transportable scale every-time the vehicle, on which the shredding system is placed, stops for shredding, setting the scale up for weighing the bins. This increases the wear and tear on the scale, which might lead to inaccurate readings. In the extreme case, the shredding operator might forget to weigh the bins, which will lead to extra work in retroactive billing or lost income for that particular shredding operation.
Therefore, there remains a need for a shredding system to automatically or semi-automatically handle the weighing of waste material in an effective manner.
It is therefore an object of the invention to provide a confidential waste material shredding system which provides an effective weighing means for material to be shredded.
In the invention, a shredding system is used comprising a vehicle having a hopper, for receiving material to be shredded, a shredder communicating with the hopper, and a holding space for shredded waste into which the shredder feeds shredded material; and a bin lifting means having at least one chain onto which is attached a carriage, the carriage having gripping means for attaching a bin, the at least one chain being movable by means of a drive mechanism from a lowered position, in which the carriage is adjacent the ground on which the vehicle is standing, and a raised position, in which the carriage is adjacent an inlet of the hopper and the content of the bin is emptied into the hopper via the inlet. The carriage has a weight measuring means arranged to measure the weight of the bin when the bin is attached to the gripping means.
Advantageously, the weight measuring means further has a weight indicating means, for displaying the measured weight of the bin.
Preferably, the weight measuring means further has a weight value storing means, for storing the measured bin weight electronically.
The system further preferably has an enclosure arranged on a side of the vehicle, the enclosure generally covering the bin lifting means and the bin during lifting and emptying of the bin.
The enclosure is preferably a three sided enclosure which is slidably arranged in the vehicle between a stored position, in which an outer wall of the enclosure is generally flush with an outer side of the vehicle, and an operating position, in which the enclosure is pulled out from the outer side of the vehicle.
The bin lifting means advantageously comprises a hydraulic drive for powering the chain. More preferably, the hydraulic drive is a large displacement hydraulic drive. The hydraulic drive advantageously drives the chain via at least one sprocket wheel.
Preferably, the bin lifting means comprises an adjustable frame, the frame being adjustable in height to facilitate the installation of the frame relative the vehicle.
Further features of the invention will be described or will become apparent in the course of the following detailed description.